but they said me that for the subject like nav and met you have to understand the subject ..
You also need to understand the other 12 subjects. I understand that you may have had an easy holiday getting your FAA fATPL, but in JAA land the effort and time required is greater.
Understanding the 14 ATPL subjects will make you a safer pilot, the knowladge and wisdom you will gain from
understanding the subjects as opposed to just learning the answers may very well prove to be what stands between life and death for yourself and hundreds of people.
Don't get me wrong, the Bristol QB is great for the exams, it
helps you understand the way exam questions are asked and need to be answered.
So, study hard, ask your Ground School Instructors questions, and all will be fine.
EpsilonVaz